sootshe Posted August 26, 2017 Share Posted August 26, 2017 Advice need on port location for a set of Cornscala's I'm putting together. Cabinet dimensions will be the same as the factory Cornwall, but the bass bin will only have the woofer in it, the mids & tops will be in a seperate cabinet on top of the bass bin. I want to mount the bass driver towards the top of the cabinet & have the same size port as the Cornwall just below the bass driver, rather than at the bottom of the bass cabinet. Anyone see any issues with doing this? Secondly, will be using the Crites 1526C woofer & when I run sims in Win ISD, it comes up with a 160 litre cab instead of the 183 litre cab of the Cornwall & the port dimensions are totally different than the Cornwalls. From research, I see that everyone uses the port dimensions of the Cornwall for the Cornscala, so a bit confused as to why this is. I'm sure the Klipsch engineers knew what they were doing when they designed the Cornwall, maybe they were aiming for a particular response or sound? 1 Quote Link to comment Share on other sites More sharing options...
Full Range Posted August 27, 2017 Share Posted August 27, 2017 Morning mate - good to see you again Crites has 4 variation plans of the Cornscala -- A, B, C, D http://www.critesspeakers.com/cornscala.html My view on the volume is - the more volume the better So use the full size dimensions of the current combined driver cabinet, and add the seperate midrange and tweeter on top of the full size bass bin Also go 25 mm thick on the panels I should also add that the Great Plains 399 8A are a superb mid range horn Quote Link to comment Share on other sites More sharing options...
sootshe Posted August 27, 2017 Author Share Posted August 27, 2017 So here's my calcs from Win ISD & I have gone with 2 round ports 90mm diameter - is this the same as the rectangular port of the Cornscala? Should I use this port combination or the standard Cornwall port? Quote Link to comment Share on other sites More sharing options...
sootshe Posted August 28, 2017 Author Share Posted August 28, 2017 No one? I just need to verify that the tuning is correct before I start building. Quote Link to comment Share on other sites More sharing options...
Full Range Posted August 29, 2017 Share Posted August 29, 2017 7 hours ago, sootshe said: No one? I just need to verify that the tuning is correct before I start building. Sorry mate I can't help as I haven't had any experience with building this speaker However I can help with Crossovers 🎶 Quote Link to comment Share on other sites More sharing options...
pzannucci Posted August 29, 2017 Share Posted August 29, 2017 12 hours ago, sootshe said: No one? I just need to verify that the tuning is correct before I start building. Port size and length depends on your end goal. Look at the db of the roll off of the woofer in that size box and adjust the port size and length accordingly. Are you looking for more extension? Less? More punchy speaker? What WinISD has shown is a -4db at 40hz. If the speakers are closer to the wall, room gain will help that box size be flat into the 30s. If that's a good goal with that positioning, you should be done. If you want more extension, shrink the port size or lengthen the port. You will likely drop in low frequency output but extend the output. Only way to maintain the output is to make the box larger if you want more extended bass. 1 Quote Link to comment Share on other sites More sharing options...
jjptkd Posted August 29, 2017 Share Posted August 29, 2017 If you want Cornwall bass stick with Cornwall dimensions and port size, anything different will be, well, different. Quote Link to comment Share on other sites More sharing options...
sootshe Posted September 4, 2017 Author Share Posted September 4, 2017 On 8/29/2017 at 9:38 PM, pzannucci said: Port size and length depends on your end goal. Look at the db of the roll off of the woofer in that size box and adjust the port size and length accordingly. Are you looking for more extension? Less? More punchy speaker? What WinISD has shown is a -4db at 40hz. If the speakers are closer to the wall, room gain will help that box size be flat into the 30s. If that's a good goal with that positioning, you should be done. If you want more extension, shrink the port size or lengthen the port. You will likely drop in low frequency output but extend the output. Only way to maintain the output is to make the box larger if you want more extended bass. Quite happy with the response, just curious as to why it's different to a Cornwall. Quote Link to comment Share on other sites More sharing options...
sootshe Posted September 4, 2017 Author Share Posted September 4, 2017 On 8/29/2017 at 11:27 PM, jjptkd said: If you want Cornwall bass stick with Cornwall dimensions and port size, anything different will be, well, different. Haven't actually heard a Cornwall, but the general response from everything I've read about Cornscala's is that the bass is significantly deeper than a LS, so will take your comment on board & also trust the Klipsch engineers & stick with the tried & proven port & cabinet dimensions. Anyone care to comment on if I move the bass driver to the top of the cab & the port to just underneath the bass driver, as to whether this will alter the sound? The bass cab will only have the bass driver in it, with the horn in a seperate cab above it. I want to get the bass driver closer to the mid horn & put the port directly under the bass driver. Quote Link to comment Share on other sites More sharing options...
pzannucci Posted September 4, 2017 Share Posted September 4, 2017 30 minutes ago, sootshe said: Haven't actually heard a Cornwall, but the general response from everything I've read about Cornscala's is that the bass is significantly deeper than a LS, so will take your comment on board & also trust the Klipsch engineers & stick with the tried & proven port & cabinet dimensions. Anyone care to comment on if I move the bass driver to the top of the cab & the port to just underneath the bass driver, as to whether this will alter the sound? The bass cab will only have the bass driver in it, with the horn in a seperate cab above it. I want to get the bass driver closer to the mid horn & put the port directly under the bass driver. Proximity to an adjacent boundary will usually increase bass. Everything when building a speaker will be subjective to what you like. The only way you will know is to build it and try it. Modeling can get you in the ballpark but that last 20% is your determination to make it sound like you want it. Quote Link to comment Share on other sites More sharing options...
consistent Posted October 4, 2017 Share Posted October 4, 2017 Hi I followed Bob Crite's build of a square box but I used the Roger Floth approach and extended the ports (article somewhere around here). The box gets down to about 28hz with a 'deeper punch' better than with the standard porting. All other drivers sit on top of the box. I used Bob's woofer, crossover and DE tweet but am using the Altec 291 (L-padded) with a Le Cleac'h horn - amazing detailed/tight/extended combination. all the best Quote Link to comment Share on other sites More sharing options...
justinsweber Posted October 4, 2017 Share Posted October 4, 2017 I can’t comment on Bobs woofer, except to say it’s very very well regarded. I’d say that looking at the Eminence 15c for simulations may help. In my experience the cabinet is too large. Shrinking the cab from ~6.5fu to 5.8cu should yield a faster, less flabby bass. I have never changed the ports dramatically. If I recall it’s 50sq in? moving the woofer up in cabinet may change things a bit (less baffle reinforcement?) but then again it might improve mid bass for you. Quote Link to comment Share on other sites More sharing options...
pzannucci Posted October 4, 2017 Share Posted October 4, 2017 5 hours ago, justinsweber said: I can’t comment on Bobs woofer, except to say it’s very very well regarded. I’d say that looking at the Eminence 15c for simulations may help. In my experience the cabinet is too large. Shrinking the cab from ~6.5fu to 5.8cu should yield a faster, less flabby bass. I have never changed the ports dramatically. If I recall it’s 50sq in? moving the woofer up in cabinet may change things a bit (less baffle reinforcement?) but then again it might improve mid bass for you. The flabby bass can be part of the box and port size and length combo. Additionally the size of the baffle and proximity of the woofer to the floor will change the sound. Ports are best made to be modified to come to a tuning that can be deep enough and fast enough for your ear. I myself like the longest port to get a large size and keep the box tuning in the hz required to extend the bass and load the driver at or below resonance FWIW. Quote Link to comment Share on other sites More sharing options...
consistent Posted October 5, 2017 Share Posted October 5, 2017 Yeah, I agree Pzannucci, that's what tuning with Floth method does: bass is tighter, faster and copes better with transients Quote Link to comment Share on other sites More sharing options...
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